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1.
Granular films prepared from well-defined In clusters embedded in Kr (? 10-40 at % Kr) show sharp resistance anomalies very close to the superconducting transition temperature. The observed resistance peak(s), which go(es) above the normal state resistance RN and which can be as high as ? 1.5 RN, can be explained by a “mesoscopic” effect: Superconducting percolation aggregates of size ξρ, larger than the superconducting coherence length ξS, but smaller than the quasiparticle relaxation length λQ*, have a superconducting gap, but are not yet able to carry a supercurrent. 相似文献
2.
3.
Werner W.K.R. Mederski Manfred BaumgarthMartina Germann Dieter KuxThomas Weitzel 《Tetrahedron letters》2003,44(10):2133-2136
An efficient one-step synthesis of 4-nitro-N-aryl substituted glutarimides, succinimides and maleimides in polyphosphoric acid is described together with the subsequent reduction to the corresponding anilines. The scope and limitation of this cyclocondensation are presented. 相似文献
4.
K. -M. Weitzel M. Penno J. Mähnert H. Baumgärtel 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,29(3):195-201
The formation of Ar 2 + ions has been investigated by means of the threshold photoelectron photoion coincidence (TPEPICO) technique. Two pathways for the formation of Ar 2 + ions are important. One is a direct path via excitation of Rydberg states of Ar2 with consecutive autoionization. The other path is dissociative ionization of larger argon clusters, in this case argon trimers. These two pathways lead to Ar 2 + ions with different internal energy. The pathways are easily distinguished in the TPEPICO-TOF spectra by the kinetic energy released (KER) in the dissociative ionization. The KER for the reaction Ar 3 + → Ar 2 + + Ar was measured as a function of the photon energy and compared to the KER expected from statistical theory. The agreement is satisfying and confirms that Ar 3 + ions do indeed dissociate at the thermochemical threshold. At higher photon energy the excited2Π(3/2)g state of Ar 3 + is also detected from a second component in the KER. By applying a kinetic energy discrimination it is possible to measure cluster ion spectra in the presence of larger clusters but essentially without interference from the latter. 相似文献
5.
6.
M. L. Jane Weitzel 《Accreditation and quality assurance》2012,17(2):139-146
The vision for metrology at the United States Pharmacopeia (USP) is for international recognition, harmonization, and official
acceptance of all USP reference standards that are based on sound, scientific, metrological principles, such as measurement
uncertainty (MU). Pharmaceutical testing laboratories will need to estimate the MU for their test procedures. This paper demonstrates
how to estimate MU for a test procedure validated following the requirements in USP General Chapter <1225>, Validation of
Compendial Procedures. The test procedure determines the assay and impurities for a pharmaceutical drug substance. Pharmaceutical
manufacturing companies are required to test the drug substance used in their drug products. In this example, a new test procedure
was developed and validated following the requirements in USP <1225>. The MU was estimated using the data from the test procedure
validation. The MU estimate determined that the test procedure was fit for use with one determination, avoiding the expense
of duplicate determinations. The MU estimate was used to set up decision rules for comparing test data to the assay and impurity
specifications. The information from the MU estimate was used to monitor the routine use of the test procedure using control
charts that assess accuracy and precision of each run based upon actual test procedure performance capability. 相似文献
7.
Irina Krasnochtanova Andreas Rauh Marco Kletting Harald Aschemann Eberhard P. Hofer Karl-Michael Schoop 《Applied Mathematical Modelling》2010
This paper presents sophisticated interval algorithms for the simulation of discrete-time dynamical systems with bounded uncertainties of both initial conditions and system parameters. Since naive implementations of interval algorithms might lead to guaranteed enclosures of all system states which are too conservative to be practically useful, we present algorithmic extensions of classical approaches which are applicable to the simulation of non-cooperative systems with time-varying uncertain parameters. Overestimation arising in the interval evaluation of dynamical system models due to the wrapping effect is reduced by an exact pseudo-linear transformation of nonlinear state equations and by new heuristics for the subdivision of interval enclosures which especially prefer splitting of unstable intervals. To highlight the typical procedure for parameterization of interval-based simulation routines and to demonstrate their efficiency, a nonlinear model of biological wastewater treatment processes is discussed. For this application, we consider the maximum specific growth rate of substrate consuming bacteria as a time-varying uncertain parameter. Only worst-case bounds are assumed to be available for the range of this parameter while no information is provided about its actual variation rate. 相似文献
8.
A. Petri Ch. Br uchle H. Leigeber A. Miller H. -P. Weitzel F. -H. Kreuzer 《Liquid crystals》1993,15(1):113-121
Photosensitive cholesteric polysiloxanes, which contain an azo dye, were irradiated with linearly polarized light. The cholesteric samples were oriented in the Grandjean texture. Before irradiation they reflected circularly polarized light in the near infrared region. For perpendicular incidence, only one order of reflection was observed. Upon irradiation with linearly polarized light, which is absorbed by the azo dye, additional reflection bands appeared in the visible part of the spectrum. It turned out that the additional reflection is caused by a new Bragg type grating which shows higher reflection orders. The formation of the grating is based on the periodic deformation of the helical ordering of the molecules. The deformation is periodic, as due to photoselection, only dye molecules in equidistant layers with a suitable orientation absorb radiation. For low exposure, the grating reflects linearly polarized light. After continued irradiation, the reflection bands disappear almost completely. High birefringence, strongly dichroic dye absorption and the loss of the reflecting properties prove that a planar nematic texture has developed. The formation of this texture from the Grandjean texture is a new example for photoinduced rotational diffusion. 相似文献
9.
J. de Brevans W. von Genersich K. Fischer O. Gruenert C. von der Heide F. Jakob A. Röhrig C. Revis K. B. Lehmann M. Marchadier O. Biernath A. Krüger J. F. Liverseege N. Evers F. H. van der Laan H. Tydens W. Friese R. M. West W. E. Hillyer Ch. H. La Wall H. A. Bradshaw W. D. Mc Abee H. W. Wiley V. Gerlach E. Rost Fr. Franz A. Weitzel und Königliche wissenschaftliche Deputation für das Medizinalwesen in Preussen 《Fresenius' Journal of Analytical Chemistry》1914,53(7):455-467
Ohne Zusammenfassung 相似文献
10.
Znakovskaya I von den Hoff P Schirmel N Urbasch G Zherebtsov S Bergues B de Vivie-Riedle R Weitzel KM Kling MF 《Physical chemistry chemical physics : PCCP》2011,13(19):8653-8658
Strong few-cycle light fields with stable electric field waveforms allow controlling electrons on time scales down to the attosecond domain. We have studied the dissociative ionization of randomly oriented DCl in 5 fs light fields at 720 nm in the tunneling regime. Momentum distributions of D(+) and Cl(+) fragments were recorded via velocity-map imaging. A waveform-dependent anti-correlated directional emission of D(+) and Cl(+) fragments is observed. Comparison of our results with calculations indicates that tailoring of the light field via the carrier envelope phase permits the control over the orientation of DCl(+) and in turn the directional emission of charged fragments upon the breakup of the molecular ion. 相似文献